From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <gcc-bugzilla@gcc.gnu.org>
Received: by sourceware.org (Postfix, from userid 48)
	id 99D623858C54; Tue, 13 Jun 2023 02:03:03 +0000 (GMT)
DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 99D623858C54
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gcc.gnu.org;
	s=default; t=1686621783;
	bh=UUTUUiY2ot7AkZBPt2GTV2iOz7isJcBdZowUN12KwkU=;
	h=From:To:Subject:Date:In-Reply-To:References:From;
	b=G1JXdxdDpGBrYooPYr4+4Qm+b7fIQkdrh0g8Tx/2xdb3y5RG+bM2vDA/DTYBDUFtM
	 6szO/yldt6oCpmQkNByErdpPrhodBQLgKMazWOCG8jqOVec00XbWvpP4c3SsiNt0dh
	 U51WLr7lfpagxrMpx3ZYFKUx73uBRk/CIVGK4ISI=
From: "vincent-gcc at vinc17 dot net" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug tree-optimization/106155] [12/13/14 Regression] spurious "may
 be used uninitialized" warning
Date: Tue, 13 Jun 2023 02:03:02 +0000
X-Bugzilla-Reason: CC
X-Bugzilla-Type: changed
X-Bugzilla-Watch-Reason: None
X-Bugzilla-Product: gcc
X-Bugzilla-Component: tree-optimization
X-Bugzilla-Version: 13.0
X-Bugzilla-Keywords: diagnostic, missed-optimization
X-Bugzilla-Severity: normal
X-Bugzilla-Who: vincent-gcc at vinc17 dot net
X-Bugzilla-Status: NEW
X-Bugzilla-Resolution: 
X-Bugzilla-Priority: P2
X-Bugzilla-Assigned-To: unassigned at gcc dot gnu.org
X-Bugzilla-Target-Milestone: 12.4
X-Bugzilla-Flags: 
X-Bugzilla-Changed-Fields: 
Message-ID: <bug-106155-4-rIwa20YOxW@http.gcc.gnu.org/bugzilla/>
In-Reply-To: <bug-106155-4@http.gcc.gnu.org/bugzilla/>
References: <bug-106155-4@http.gcc.gnu.org/bugzilla/>
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: quoted-printable
X-Bugzilla-URL: http://gcc.gnu.org/bugzilla/
Auto-Submitted: auto-generated
MIME-Version: 1.0
List-Id: <gcc-bugs.sourceware.org>

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D106155

--- Comment #12 from Vincent Lef=C3=A8vre <vincent-gcc at vinc17 dot net> -=
--
Here's a similar, simpler testcase:

int f1 (void);
void f2 (int);
long f3 (long);

void tst (void)
{
  int badDataSize[3] =3D { 1, 1, 1 };

  for (int i =3D 0; i < 3; i++)
    {
      int emax;
      if (i =3D=3D 2)
        emax =3D f1 ();
      int status =3D f3 (badDataSize[i]);
      if (f1 ())
        f1 ();
      if (status)
        f1 ();
      if (i =3D=3D 2)
        f2 (emax);
    }
}

gcc-12 (Debian 12.2.0-14) 12.2.0 warns at -O1, but not at -O2.
gcc-13 (Debian 13.1.0-5) 13.1.0 is worse, as it warns at both -O1 and -O2.=